Canon 6D Exposure

Saturation & Hue Accuracy
Good saturation levels with very good hue accuracy.

Saturation. The Canon 6D produces images with about average saturation levels at default settings. Strong reds, orange, dark brown, dark green, and dark blues are pushed small to moderate amounts, while other colors are close to bang on or slightly desaturated. The mean saturation of 111.3% (11.3% oversaturated) at base ISO is typical for DSLRs, and remains fairly consistent through the ISO range, dropping off only at the highest ISOs. Good performance here. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. When white balance is set manually, lighter Caucasian flesh tones shot with the Canon 6D appear natural, with appropriate saturation levels and accurate color, just slightly on the pinkish side. Darker skin tones show only a small nudge toward orange. Good results here as well. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.

Hue. The Canon 6D's hue accuracy is very good, much better than average. There are the usual shifts in cyan toward blue (actually quite small compared to most cameras), red toward orange, and orange toward yellow, but all are fairly minor. (The cyan to blue shift is very common among the digital cameras we test; we think it's a deliberate choice by camera engineers to produce better-looking sky colors.) Average "delta-C" color error is only 4.36 at base ISO which is very good (smaller numbers are better), and remains low across the ISO range. Hue is "what color" the color is.

Saturation Adjustment
The Canon EOS 6D offers a total of nine saturation settings, four above and four below the default saturation, which is quite a wide range. As it should, the Canon 6D's saturation adjustment affects only the saturation, leaving the contrast of the image unaltered. (In some cameras, saturation tends to affect contrast, and vice versa.) The fine steps between settings mean you can program the camera to just the level of saturation you prefer. Well done.

The table above shows alternate settings including the default as well as the two extreme saturation settings. Click on any thumbnail above, then click again to see the full-sized image.

Exposure and White Balance

Indoors, incandescent lighting
Auto and Incandescent settings both struggled with household incandescent lighting, though Manual white balance produced a much more neutral image. Higher than average exposure compensation required.

Indoors, under incandescent lighting, the Canon EOS 6D's Auto and Incandescent white balance settings both struggled, resulting in strong reddish and orange casts respectively. Unfortunately, this is quite common among cameras we've tested, but disappointing nonetheless. The Manual setting produced nearly accurate results, though just slightly cool and a touch green overall. The 2,600 Kelvin setting which should match the temperature of our lights produced similar results to Manual, just a touch cooler with a very slight blue tint. The Canon 6D required +1.0 EV exposure compensation for these shots, which is significantly higher than the +0.3 EV average among the cameras we've tested. (Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.)

Outdoors, daylight
Color and saturation are very good,, though with a tendency to underexpose.

Outdoors, the Canon EOS 6D tends toward a slightly cool color balance, though overall color was generally very good in our shots. We prefer the slightly pinker skin tones from the Manual white balance setting in our "Sunlit" portrait shot above left, but Auto white balance was pretty close. The Canon 6D tends to underexpose a bit, requiring higher than average exposure compensation. Here, even at +1.0 EV, our "Sunlit" portrait is a bit dim, while most cameras need +0.7 EV compensation for this shot. The Canon 6D's default contrast is a little high, as most users prefer, though the camera's contrast, Auto Lighting Optimization and Highlight Tone Priority settings do help with this difficult lighting quite a bit. See below for examples of this. The Far-field shot (above right) is also a touch cool, and default exposure is also dim.

Note that different lenses were used for these shots (our very sharp Sigma 70mm f/2.8 Macro reference lens for the shot on the left, and a Canon 50mm f/1.8 II lens on the right), yet both shots were underexposed with multi-segment metering, so we don't think the third-party lens is at fault for the dim exposures.

See full set of test images with explanations
See thumbnails of all test and gallery images

Resolution
~2,400 lines of strong detail from JPEGs, slightly higher from RAW.

Our laboratory resolution chart shows strong detail with distinct line patterns to just over 2,400 lines per picture height horizontally and to about 2,400 lines vertically from in-camera JPEGs. Extinction of the pattern occurred just past 3,400 lines horizontally and vertically. Adobe Camera Raw converted .CR2 files show slightly higher resolution than the in-camera JPEGs, perhaps 100 lines more in both directions, but complete extinction of the pattern was extended to the limits of the chart in the horizontal direction, and to about 3,800 lines in the vertical direction. While ACR was able to extract a bit more detail, it also produced more color moiré than JPEGs from the camera, though that's not unusual. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Very good sharpness with loads of detail, though some sharpening artifacts are visible. Some minor detail loss to noise reduction processing even at base ISO.

Sharpness. The Canon 6D's 20-megapixel sensor captures excellent levels of image detail when coupled with a good lens, though some edge-enhancement artifacts such as sharpening halos are visible around high-contrast edges at default settings, as shown in the crop above left. (The above crop of our "Pine" shot was taken with a Canon EF 50mm f/1.8 II lens which is very sharp when stopped-down to f/8.) Pros shooting JPEGs may want to turn in-camera sharpening down a few clicks, and sharpen in post. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.

Detail. The crop above right shows some minor detail loss due to noise suppression at base ISO. You can see some smudging of lower contrast and darker strands of hair, but performance here is still quite good, especially given the resolution. (The crop above of the hair taken with our very sharp Sigma 70mm f/2.8 reference lens.) Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

RAW vs In-Camera JPEGs
As mentioned above, the Canon 6D does an excellent job of capturing sharp, detailed JPEGs when coupled with a sharp lens, but as is usually the case, slightly more detail can be preserved while producing fewer sharpening artifacts by carefully processing its RAW files.

In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking on the link will load the full resolution file. Examples include in-camera Fine JPEG, RAW file processed through Canon's Digital Photo Professional (DPP) software using default settings, and finally, the same RAW file processed through Adobe Camera Raw (ACR) version 7.4, then sharpened in Photoshop using 250% unsharp masking with an 0.3 pixel radius.

Canon's DPP software produced an image very similar to the in-camera JPEG, as expected from a company that develops its own conversion software. The RAW image processed through ACR and then moderately sharpened in Photoshop contains improved detail compared to the in-camera and DPP-processed images, with less obvious sharpening halos. As is usually the case, users wanting to extract the most detail from their Canon 6D will want to shoot RAW and use a good RAW converter.

ISO & Noise Performance
Excellent high ISO performance, with good detail versus noise tradeoff up to ISO 6,400.

The Canon EOS 6D's high ISO performance is excellent up to ISO 1,600 in the relatively dim indoor lighting used here. Sure, there's a gradual loss of fine detail as ISO increases from base ISO, but remaining detail is still very good to ISO 1,600. At ISO 3,200 we begin to see some moderate detail loss as stronger noise reduction blurs subtly contrasting detail, as well a touch of chroma noise in darker areas, but results here are still quite good. At ISO 6,400 noise grain becomes coarser, blurring stronger, and chroma noise more apparent, but there's still a lot of detail left to work with. Noise and the effects of noise reduction really become apparent at ISO 12,800, with much stronger blurring and more noticeable grain. At ISO 25,600 and above, fine detail really deteriorates quickly, with obvious chroma blotching and high pixel noise exacerbated by relatively strong default sharpening, especially at ISO 102,400. Saturation also drops off slightly above ISO 12,800, probably in an attempt to mitigate chroma noise.

Overall, though, excellent high ISO performance that's very similar to Canon 5D Mark III's, though with slightly higher default noise reduction. See the Print Quality section below for our evaluation of maximum print sizes at each ISO setting.

A note about focus for this shot: We shoot this image at f/4, using one of three very sharp reference lenses (70mm Sigma f/2.8 macro for most cameras, 60mm f/2.8 Nikkor macro for Nikon bodies without a drive motor, and Olympus Zuiko 50mm f/2.0 for Four Thirds and Micro Four Thirds bodies). To insure that the hair detail we use for making critical judgements about camera noise processing and detail rendering is in sharp focus at the relatively wide aperture we're shooting at, the focus target at the center of the scene is on a movable stand. This lets us compensate for front- or back-focus by different camera bodies, even those that lack micro-focus adjustments. This does mean, though, that the focus target itself may appear soft or slightly out of focus for bodies that front- or back-focused with the reference lens. If you click to view the full-size image for one of these shots and notice that the focus target is fuzzy, you don't need to email and tell us about it; we already know it. :-) The focus target position will simply have been adjusted to insure that the rest of the scene is focused properly.

Extremes: Sunlit, dynamic range and low light tests
Very high resolution with strong detail, though somewhat high contrast. Highlight Tone Priority, Auto Lighting Optimization, and contrast adjustment options do a good job of dealing with harsh lighting. Excellent low-light performance.

The Canon EOS 6D produced moderately high contrast, though because of the exposure issue, our entire "Sunlit" portrait exposure series is underexposed. We obviously prefer the +1.0 EV exposure here, but it's still a bit dim in the face so a bit more exposure compensation is needed. You can see in the +1.0 EV shot that while most highlights are intact, shadows are very dark and if you look closely, very deep tones are just a touch noisy and posterized. Still, pretty good performance here (except for the underexposure issue).

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here. In actual shooting conditions, be sure to use fill flash in situations like the one shown here; it's better to shoot in open shade whenever possible.)

Face Detection
Just like most point & shoot cameras these days, the Canon EOS 6D has the ability to detect faces in Live View mode, and adjust exposure and focus accordingly.

As you can see from the examples above, it works, as the center image with face detection enabled is better exposed for the face (though still slightly dim) than the left image where face detection was not employed. Scene Intelligent Auto (right image) produced an image with slightly better exposure than our default image, though it's still quite dim, unfortunately. Auto mode also selected a much wider aperture (f/5), making the depth of field shallower which helps to isolate the subject from the background, though the camera seemed to focus on the flowers in this case while leaving the mannequin out of focus. (When shooting portraits at wide apertures, it's best to manually place the focus point over an eye.)

Contrast Adjustment
We really like it when a camera gives us the ability to adjust contrast and saturation to our liking. It's even better when those adjustments cover a useful range, in steps small enough to allow for precise tweaks. As was the case with its saturation adjustment, the Canon 6D's contrast setting meets both challenges very well.

At its lowest contrast setting, the Canon 6D did a good job of preserving highlight detail at +1.0 EV compensation, while bringing out shadow detail. It also helped with highlights and dark shadows in our Far-field shot at default exposure. Overall, very good results here, with the contrast adjustment working on both highlights and shadows.

The Canon 6D's contrast-adjustment control offers a very broad range of control in usefully fine gradations, and does a good job of adjusting contrast without affecting color saturation in the process. (As noted earlier regarding saturation adjustment, something that not all cameras manage to do.)

Highlight Tone Priority
The Canon 6D's Highlight Tone Priority (HTP) option did an excellent job of preserving highlight detail, as shown below. (Mouse over the Off and On links to load the corresponding thumbnail, histogram and crops.)

Both shots above were captured at +1.0 EV (the default exposure was underexposed, and had few highlights to protect), the only difference being that HTP was enabled for the second shot which necessarily increases the ISO to 200; part of how HTP works. The result is evident in the histograms and crops above, clearly showing the superior highlight preservation when HTP is enabled, while shadows were only minimally impacted. As you can see from the shadow crops, an increase in noise is however the price you pay when ISO is boosted from 100 to 200. (Note that levels were highly boosted in the shadow crops to reveal the increase in noise.) Except in the very deepest shadows, though, visible noise is so low at ISO 200 that this is really a negligible tradeoff.

Auto Lighting Optimization
Like other recent EOS models, the Canon 6D offers three selectable levels of Auto Lighting Optimization (ALO), plus Off. In Auto exposure mode, ALO is automatically enabled at the Standard level. All four shots below were taken with the same +1.0 EV exposure setting.

Mouse over the links on the left to load the associated thumbnail and histogram, and click on the links to load full resolution images. As you can see, ALO has the effect of shifting shadows and mid-tones in the histograms to the right, brightening shadows and indeed most of the image without clipping additional highlights, making it a useful feature for high contrast shots like this. We liked the results the higher settings yielded here. ISO is not boosted for ALO so increased noise is not an issue, though it may be slightly more visible in shadows that have been boosted significantly.

HDR Capture
The Canon 6D has a High Dynamic Range (HDR) capture mode where the camera takes three images (underexposed, normal, and overexposed) in quick succession and combines them in-camera into one image. If performed properly, this method should result in much higher dynamic range, without the additional noise penalty that comes with boosting sensitivity when using the HTP option. (In fact, it can reduce shadow noise by combining shadows from the overexposed shot.) There are four HDR settings available: Auto, ±1 EV, ±2 EV, and ±3 EV. There are also options for Continuous HDR (1 shot only or Every shot until cancelled), and Auto Image Align (Enable or Disable). The Canon 6D does not save the three individual images, and as you'd expect, RAW format is not supported.

Rollover the links above to compare the available exposure settings, and click on the links to access full resolution images.

As you can see, dynamic range is improved with shadows boosted and strong highlights tamed, however the resulting HDR images are still a touch dim overall. Watch out for ghosting and other artifacts when the scene is not entirely static (for example, you can see ghosting of the flags in the above images). For this reason, HDR is not recommended for live or moving subjects.

Dynamic Range
A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data "saturates" at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier "useful" in there: While it's tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)

What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.

JPEG. The graph at right (click for a larger version) was generated using Imatest's dynamic range analysis for an in-camera Canon 6D JPEG file with a nominally-exposed density step target (Stouffer 4110). At default camera settings and base ISO, the graph shows 11.5 f-stops of total dynamic range, with 8.38 f-stops of dynamic range at the "High" quality level. These are pretty good numbers numbers for JPEGs, and slightly improved over the Canon 5D Mark III which only managed 7.8 f-stops at the High quality level, though the High quality score is still quite a bit lower than the best full frame models. Note though that this measurement has a margin of error of about 1/3 f-stop, so differences of less than 0.33 can be ignored.

RAW. The graph at right is from the same Stouffer 4110 stepchart image captured as a raw (.CR2) file, processed with Adobe Camera Raw using the Auto setting then tweaked from there. The Canon 6D's RAW file scored 1.5 f-stops more in total dynamic range (13 vs 11.5 f-stops), but the score at the highest quality level decreased slightly to 8.23 f-stops which is an insignificant difference compared to JPEGs. This is due to the somewhat higher noise in the 6D's darker shadows, as indicated when comparing the bottom-left Pixel Noise plot in the Imatest chart. These numbers are again a slight improvement over the 5D Mark III which managed 7.87 at the highest quality level and 12.5 f-stops total, however still not as good as the best full-frame cameras from competitors. The Nikon D600 for instance managed a significantly better score of 10.5 f-stops at the highest quality level.

Low Light. The Canon 6D performed very well on the low-light test, capturing bright images at the lowest light level (1/16 foot-candle), down to the base ISO of 100, though ISO 50 shots are dim at the lowest light levels (limited by the longest non-bulb mode shutter speed of 30 seconds).

As expected, noise increases as ISO goes up and light levels go down, but noise remains well-controlled to ISO 12,800. There were a few hot pixels at low ISOs, but nothing unusual. Some faint banding can be seen in darker areas at very high ISOs, especially with noise reduction turned down, but that's not unusual either, and shouldn't be a problem for properly exposed subjects. Some minor heat-blooming can also be seen in the lower-right corner at very high ISOs, but that's also not unusual at such high sensitivities.

Color balance was pretty good, just a touch cool with Canon 6D's Auto white balance setting even at high ISOs, though at lower light levels white balance shifted slightly towards magenta.

When using the optical viewfinder and phase-detect AF, the Canon 6D's autofocus system was able to focus on the subject down to below the 1/16 foot-candle light level unassisted with an f/2.8 lens, which is excellent. Note that the Canon 6D does not have an AF assist lamp (it uses the one provided on most flash units). In Live View mode using contrast-detect AF, the Canon 6D was able to focus down to just above 1/16 foot-candle unassisted, which is very good.

The Canon 6D's Multi Shot Noise Reduction mode takes a burst of four images and blends them together to average out noise. It really makes a difference at higher ISOs, making very high ISOs like 12,800 and above much cleaner. Compare the crops above taken at the same light level (1 foot-candle) at ISO 25,600.

As always, keep in mind that the longer shutter speeds here demand the use of a tripod to prevent any blurring from camera movement. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) Digital SLRs like the Canon 6D do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Print Quality
The Canon 6D prints superb images. Stunning 30 x 40s at ISO 50/100/200; an excellent 16 x 20 at ISO 1600; and a good 5 x 7 all the way to ISO 25,600.

ISO 50/100/200 images look terrific at 30 x 40, with sharp detail and rich colors. Makes a nice wall display print up to 40 x 60.

ISO 400 prints look great at 24 x 36 inches, crisp and vibrant, and are fine for wall display up to 36 x 48.

ISO 800 prints remain sharp up to 20 x 30, introducing some minor luminance noise in shadows and softness in our red swatch at 24 x 36 inches but still quite usable for less critical applications.

ISO 1600 makes an excellent 16 x 20 inch print, while 20 x 30s here show some noticeable loss of contrast in our target red swatch.

ISO 3200 prints a very nice 13 x 19, with 16 x 20s losing some contrast in our mosaic bottle but still fine for wall display prints.

ISO 6400 yields a good 11 x 14 inch print, with good color renditioning for such a high ISO.

ISO 12,800 prints a good 8 x 10, though is starting to introduce some loss in color fidelity and a bit more noise in some shadowy areas.

ISO 25,600 makes a nice 5 x 7 inch print.

ISO 51,200 prints a good 4 x 6, if just a bit on the grainy size.

ISO 102,400 does not print a usable 4 x 6 and is best avoided.

With a full-frame sensor and 20 megapixels, it should come as no surprise that the Canon 6D prints look excellent in comparison to all but the best cameras out there today. But with its relatively low price tag for a full-frame camera, this model will surely draw attention to anyone wanting to step up to this level of quality without breaking the bank to do so.